The purpose of this paper is to describe a volume determination and reconstruction method applied to tree volume calculation for stem analysis. The issues involved in the detection and analysis of tree volume from the rings are not unique to the application, but are likely of interest to anyone developing volume calculation from planar sections. A digital method was developed to detect growth rings (contours) to stem analysis. Then, it was used a technique based on a tridimensional Delaunay triangulation which establish the correspondence between adjacent planar sections. Thirty discs of Pinus elliottii were taken at various heights along the stem and photographed with a digital camera while still at the forest. Volumes per age were estimated using the 3D model reconstructed and compared with conventional analysis.